Wet cell electric storage batteries such as those used in industrial traction batteries typically include a battery cover having an opening providing communication with a battery cell. The opening facilitates access to the battery cell for initial filling with electrolyte and permitting the fluid level to be checked and corrected occasionally during the life of the battery. A vent cap is typically provided that is removeably received in the opening. The vent cap permits the controlled venting of gases generated during the discharging and the recharging of the battery.
Prior art battery vent caps such as those illustrated in U.S. Pat. Nos. 7,556,056, 6,228,525, and 4,696,874 have included a fluid fill path formed therein which permits the addition of fluid to the battery cell without removing the vent cap from the opening. These prior art vent caps also include a float mechanism associated with a valve, wherein the float mechanism and the valve cooperate to open and close the fluid fill path at predetermined fluid levels within the battery cell. An inherent problem with the float mechanism and the valve in the prior art vent caps is the valve restricts the flow of water through the fluid fill path which increases a time required to fill the battery cell. Another inherent problem with the float mechanism and the valve in the prior art vent caps is fluid is discharged from the fluid fill path onto the float mechanism which can result in a malfunction of the float mechanism causing an undesired opening and closing of the fluid fill path by the valve.
It would be desirable to produce a vent cap for a battery cell having a float mechanism and an associated valve adapted to open and close a fluid fill path within the vent cap which minimizes a time required to fill the battery cell with a fluid and militates against an undesired opening and closing of the fluid fill path by the valve.